Method and apparatus for cracking hydrocarbon oils



sept. 14, 1954 R. A. FINDLAY METHOD AND APPARATUS FOR CRACKING HYDROCARBON OILS I4 2O l2 17 L I6 |5 I8 13 2526 I9 t2224 X I 27 /)--J\\ RECOVERY SYSTEM Filed Nov. 13 1950 IN VEN TOR.

R.A. FINDLAY A TTORNEVS Patented Sept. 14, 1954 METHOD AND APPARATUS FOR CRACKING HYDROCARBON OILS Robert A. Findlay, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Application November 13, 1950, Serial No. 195,416

11 Claims. l

This invention relates to the conversion of hydrocarbon oils. In one of its more specific aspects it relates to a method for cracking heavy residual oils at high temperatures. In another of its more specific aspects it relates to an improved apparatus for cracking heavy residual oils at high temperatures.

Heavy residual oils have long posed a considerable problem in the petroleum industry. Although refining techniques of the petroleum industry have improved greatly during the past several years, heavy residual oils have been of little or no value because of the very great tendency of such materials to form and deposit coke, tar, or other carbonaceous deposits in rening equipment. As the demand for petroleum products has increased, that demand has placed a greater burden upon the natural resources of the world and has focused attention more directly upon what heretofore had been deemed waste materials. Heavy residual oils have been very closely akin to waste materials, and it is believed, therefore, that any process which aids in the utilization of such materials is of very great importance.

Many processes have been set forth in the petroleum art by which it has been proposed to crack heavy residual oils to provide normally lighter materials such as hydrogen and hydrocarbone and gasoline stocks. As pointed out above, however, the tendency for such materials to form carbonaceous deposits has made such processes relatively uneconomical. I have devised a process and an apparatus whereby the tendency of such heavy residual oils to form tarry and carbonaceous materials is utilized to a considerable extent so as to actually obtain beneiit therefrom. Recent developments in the cracking of heavy residual oils have led. to the utilization of the so-called pebble heater apparatus for converting such oils at high temperatures.

So-called pebble heater apparatus utilize a gravitating mass of solid heat exchange material, which mass is heated to a high temperature by passing hot gas therethrough in a first direct heat exchange step and is then caused to contact reactant materials, furnishing heat thereto in a second direct heat exchange. The conventional pebble heater apparatus generally comprises two chambers which may be disposed in substantially vertical alignment. The solid heat exchange material is introduced into the upper portion of the rst chamber. That material forms a gravitating bed of solid heat exchange material which iiows downwardly through the chamber in direct heat exchange with hot gaseous heal? cxchange material. The solid heat exchange material is heated to a high temperature in the heat exchange and is then gravitated to a second chamber in which the hot solid heat exchange material is caused to contact reactant materials in a second direct heat exchange relation, furnishing heat for the treatment or conversion of the reactant materials.

When such apparatus has been utilized in the cracking of heavy residual oils, it has been customary to introduce those oils directly onto the pebbles within the reaction chamber so as to coat the surface of the hot pebbles therein and thus vaporize a portion of the oil, converting the balance thereof to coke. During such operation, considerable splashing of the oil has been encountered upon its introduction into the reaction chamber. It has been found, however, that when such splashing occurs a tar mist is formed, which mist passes on through the pebble bed and is collected as a portion of the gaseous product from the reaction chamber. Such tar mists are very undesirable in the finished product and, therefore, it is necessary to carry out a separation of such materials from the desired product.

I have conceived a means and method whereby the formation of tar mists and its concomitant recovery as a portion of the reaction product is substantially obviated. Broadly speaking, this invention comprises heating a heavy residual oil to a temperature suitable for flashing and preferably toa temperature at least about its initial boiling point, gradually introducing the heated oil into the upper portion or flash zone of a reaction chamber which contains a plurality of baiiles above the top surface of the pebble bed contained therein. The heated oil is gradually introduced into the flash zone through a perforate header and is allowed to drip onto the baiiies immediately below each header, allowing the oil to be spread thereover in thin lms. The oil flashes in this portion of the reaction chamber with practically no formation of tar mist. Any minute amount of tar mist which is formed is knocked down by other baffles in the ash zone. Vapors from the upper portion of the reaction chamber are passed upwardly into a vapor phase reaction chamber in which the flashed vapors are converted to high purity olens. Liquid which drains from the surface of the plurality of baiiies within the upper portion of the reaction chamber gravitates onto the surface of pebbles within the pebble bed. A portion of the liquid material is converted by the heat exchange with the hot pebbles and forms a gaseous effluent which is collected in the upper portion of the pebble bed and is removed therefrom as a desired product of the reaction. rPhe unvaporized oil is converted to coke in and on the surface of the pebbles. With suf@- ciently porous pebbles the tar is sufficiently removed from contactable points on the periphery of the pebbles that a tendency for the pebbles to stiel; together and cluster is substantially obviated. The coke is subsequently oxidized for the purpose of heating the pebbles so as to provide necessary heat for the conversion of the residual oils.

Solid heat exchange material which may be utilized in the pebble heater system of this invention is generally termed pebbles7 The term pebbles as used herein denotes any substantially solid material of flowable size and form which has suiiicient strength to withstand mechanical pressures and the temperatures encountered within the pebble heater system. These pebbles must be of such structure that they can carry large amounts of heat from one chamber to another without rapid deterioration or substantial breakage. Pebbles which may be satisfactorily used in this oil conversion system may be substantially spherical in shape and range from about one-eighth inch to about one inch in diameter. The pebbles are preferably of a size within the range of from one-eighth inch to five eighths inch in diameter. Materials which may be used single or in combination in the formation of such pebbles include among others alumina, silicon carbide, periclase, beryllia, mullite, nickel, cobalt, copper, iron, magnesia, and silica. 1t is preferred that the pebbles be very porous, similar in structure to a sponge.

Pebbles which are preferred for the operation of the process described herein are very porous pebbles which can hold relatively large amounts oi carbon without forming pebble clusters. These pebbles are preferably formed from the material described above, but are prepared by a particular process of pebble manufacture. During the mixing stage of the pebble, a material is added thereto such as ne particles of coke, ammonium chloride, or ammonium carbonate. Such iine materials when removed from the pebbles result in a esired pore size, the fine materials being controlled as to size before incorporation in the pebble mass. The water content of the pebble mixture is controlled within the range of between 12 per cent and 18 per cent by weight and after the pebbles have been extruded or cut into small pieces they are rolled in a ball mill or are tumbled in a zone containing additional small particles of colic, ammonium chloride, or ammonium carbonate in such a manner that the small particles are 4car-.sed to be imbedded in the surface of the pebbles. After the small particles are decomposed during heating the pebbles have very large pores, somewhat akin to a sponge. If rolling in a ball mill is the method utilized in the formation of the pebbles, a plate having relatively pointed teeth thereon may be utilized as one of the rolling surfaces so as to mechanically provide desired indentations in the surface or the pebbles. The pebbles are heat treated at a temperature in the neighborhood of 2500 F. so as to cause the fine particles added during mixing of the pebbles to be decomposed over a somewhat lengthy heating period. The pebbles are also hardened during such heating so as to obtain the desired properties for resistance of abrasion and fracturing.

An object of this invention is to provide an improved method for converting heavy residual oils. Another object of the invention is to provide an improved system for cracking heavy residual oils. Another object of the invention is to provide a method for cracking heavy residual oils by heat treatment in pebble heater apparatus without a substantial formation of tar mist therein. Another object of the invention is to provide an improved pebble heater apparatus for particular use in the conversion oi heavy residual oils to lower boiling products. Another object of the invention is to provide an improved method ior producing pebbles. Other and further objects and advantages will be apparent to those skilled in the art upon study of the accompanying disclosure and the drawings.

More complete understanding oi the invention will be obtained upon reference to the schematic drawings in which Figure l is a diagrammatic 'P elevation, partly in section, of the improved pebble heater apparatus of this invention, Figure 2 is a broken section view of the upper portion of the reaction chamber of Figure l.

Referring p-articularly to the device shown as Figure l of the drawings, pebble heater chamber H is an upright, elongated chamber which is closed at its upper and lower ends by closure members l2 and i3, respectively. Pebble inlet conduit ill is provided in the upper end ci pebble heater chamber l i, preferably in closure member I2. Inlet header member l5 is provided about the lower end portion of pebble heater chamber li, preferably around closure member i3, and communicates with the interior of chamber il through the wall thereof. inlet conduit having iiow control valve li' therein, connected to header member I as is inlet conduit it; having flow control I9 provided therein. Gaseous eluent conduit 2i) is provided in the upper portion of chamber H, preferably in closure member I2. Vapor phase reaction chamber 2l is an upright elongated chamber being closed at its upper and lower ends by closure members 2E and respectively.

Pebble conduit 211 extends downwardly trom closure member I3 of chamber E i into the interior of chamber 2l, preferably substantially coaxial with each chamber. It is within the scope or this invention to provide a plurality of pebble conduits between the lower portion of chamber l and the upper portion or" chamber 2 Such pebble conduits would be disposed so as to be uniformly distributed over the outlet and inlet areas of the respective chambers. Inlet conduit 2E, having dow control valve 2G provided therein, extends, into pebble conduit 2d so as to provide inlet means for introduction of a sealing gas into conduit 24. Gaseous effluent outlet conduit 2'! eX- tends from the upper portion of vapor phase reaction chamber 2! to a recovery system 28. Gaseous effluent conduit 29 extends from recovery system 28 to a disposal point, not shown. Liquid effluent conduit 3l extends from recovery system 28 to a disposal point, not shown. Liquid phase reaction chamber 32 is an elongated upright chamber being closed at its upper and lower ends by closure members 53 and respectively. Pebble conduit 35 extends downwardly from the lower portion of vapor phase reaction chamber 2l into the interior of reaction chamber 32. Pebble conduit 213 and pebble conduit 35 extend a substantial distance downwardly into the respective reaction chambers so as to provide considerable void spaces between their lower ends and the upper end closure members of the respective rea ction chambers. Pebble conduit 35 preferably extends coaxially with both reaction chamber 2l and reaction chamber 32.

In this specific modication of the invention, a pebble support member 36 is provided within the lower portion of vapor phase reaction chamber 2! and surrounds and supports the inlet end oi pebble conduit 35. Pebble support member 35 is provided with perforations '3l uniformly distributed therethrough so as to permit the passage of gaseous materials but so as to prevent gravitation of pebbles therethrough. Gaseous eluent con-- duits 38 extend from the upper portion of reaction chamber 32 to the lower portion of vapor phase reaction chamber 2l at a point below pebble support member 36. Pebble support member St is preferably a refractory self-supporting arch which is capable of supporting a large amount of weight in addition to its own weight.

Although chamber 2l has been specifically described as containing pebble support member 36, chamber 2i may also be constructed so as to omit support member 3S. In such construction pebble conduit 35 would extend downwardly from the bottom of chamber 2l. A bustle ring would be constructed so as to encircle the lower portion of chamber 2l and would communicate with the interior of that chamber through the walls thereof. Conduits 38 would then be connected to the bustle ring which would form a gas distributing zone. A plurality of circular, downwardly extending bafdes and circular inlet headers are provided to encircle the outlet end of pebble conduit 35. Better understanding of this system of bales will be obtained upon reference to the description :M

of Figure 2 hereafter. The bailes are provided with lower edges which have a saw tooth appearance. The saw tooth structure of the bales makes possible a more uniform distribution of oil from each baille. A perforate baffle 39 is provided a short distance below the outlet end of pebble conduit 35, preferably coaxial therewith. A balltype inlet header Iii is provided within the upper portion of baille 3S and is connected to inlet conduit i2 having iiow control Valve i3 provided therein. Outlet openings are provided in header it! which extend downwardly parallel to the surface of baiiie 39. immediately below header il is a baille member le which extends across a consderable portion of the horizontal cross-section :f:

of baffle .i9 but is preferably coaxially positioned therein. Outlet header S5 is provided within the lower portion of the interior of baffle member te below baiile member it and is connected to cutlet conduit de which is, in turn, connected to re- .5:-

covery system d?. Gaseous erlluent conduit i3 extends between recovery system 3l and a disposal point, not shown. Liquid eiiluent conduit i9 extends between recovery system il and a disposal point, not shown. Header member 5l encircles at c,

least a portion of the lower part of reaction chamber 32, preferably closure member 35i, and communicates with the interior of reaction chamber E32 through the walls thereof.

Pebble outlet conduit 52 is provided in closure member 34 of reaction chamber 32 and is divided into pebble outlet conduits 53 and dit. Pebble outlet conduit 53 extends downwardly into the central portion of heater chamber 55. inlet conduit 56 is provided within the upper portion of heater 55 and above the pebble bed therein, preferably forming a coil about pebble outlet conduit 53 within the upper portion of heater 55 and extending from heater 55 to connect with header member 5l and has now control valve 57 provided therein. Pebble outlet conduit 5d is connected at its lower end to the lower end portion of elevator 5t. Elevator 58 is connected at its upper end portion to pebble inlet conduit lli in pebble heater chamber il. Elevator 58 may be a gas lift-type elevator or may be a mechanical elevator, such as a bucket elevator or a helical screw-type elevator. Pebble feeder 59 is provided intermediate the ends of pebble conduit 5d and may be any conventional type pebble feeder such as a star valve, a vibratory feeder, a gate valve, or a rotatable table-type feeder. Pebble outlet conduit 6i eX- tends from the lower end portion of heater chamber to the lower end portion of elevator 53.

` Conduit 6i may be inclined sufficiently to permit pebbles to gravitate therethrough or may be provided with a Imechanical feeder such as a helical conveyor. Inlet conduit 62, having ilow control valve E3 provided therein, extends into the lower end portion of heater chamber 55. A mechanical stoker may be provided instead of heater 55 to burn a small amount of coke from pebbles for heating steam.

Referring particularly to Figure 2 of the drawings, closure member 33 of reaction chamber 32 is preferably provided with a partial lining dit so as to direct gaseous materials upwardly and outwardly away from pebble conduit 35 to gaseous effluent conduits 33. Header members 55 which are of diierent diameters are provided so as to preferably coaxially encircle the lower end portion of pebble conduit S5. Baile members te also surround the lower end portion of pebble conduit 35 and extend downwardly from within the ircle formed by each of the header members G5 and outwardly to a circle at least as large as the outer diameter of the circle formed by the nearest header member t5. Each baiile member El extends inwardly and downwardly from a circle having at least as great a diameter as that formed by the inner diameter cf adjacent header member which surrounds its lower end portion. Individual baile members 5l' preferably have curved cross-sections and extend into the circles formed by the upper end portions of baille members Barile members @e extend upwardly from within circles formed. by closely encircling 'oa-files and upwardly and outwardly therefrom so as to overlap the baffles el which surround their lower portions. Headers are connected to heater Se by inlet conduit lll which is divided into a plurality of branches which are provided with ilow control valves therein. Header members d5 are provided with a plurality of perforations spaced about their upper sides and may also be provided with saw tooth-like extensions along their lower surfaces so as to more evenly distribute dripping of the oil introduced through the headers.

I have conceived a process which is conveniently adaptable to the operation of the specinc apparatus set forth above. This process is, therefore, particularly described in connection with the specific apparatus. Pebbles are introduced into the upper portion of pebble heater chamber il through inlet conduit le and form a gravitating gas-pervious mass therein. These pebbles are preferably covered and contain in their porous structures a substantial amount of coke material, Air is introduced into chamber l l through inlet conduit iii and a sufficient amount of water is introduced into that chamber through conduit i8 to temper the pebble temperatures therein. Air which is introduced into pebble hea-ter chamber Il oxidizes the carbon carried .on the surface of the pebbles and suicient water is introduced thereinto to control the temperature of the pebbles at between 1300 F. and 1800 F. The pebbles which are heated in this manner are gravitated from pebble heater chamber H through pebble conduit 26 into the upper portion of vapor phase reaction chamber 2 l. As pointed out above, it is desired to utilize very porous pebbles in this process.

A sealing gas, such as steam or a normally gaseous hydrocarbon, is introduced into pebble conduit through inlet conduit 25. This sealing gas prevents the flow of combustion products and reaction products between pebble heater chamber i l and vapor phase reaction chamber 2 I. IThe pebbles are introduced into vapor phase reaction chamber 2i at a temperature between about 1100 F. and 1600 F., preferably between 1l50 F. and 1350 F. The pebble mass is gravitated through chamber 2| into the upper portion of reaction chamber 32 and flows downwardly over the surface of bafe member 39. The pebbles are preferably introduced into liquid phase reaction chamber 32 at a temperature between about 900 F. and 1400" F., preferably between 950 F. and 1100 F. A hydrocarbon oil having an API gravity above about 10 and preferably within the limits of between 10 and 25 is heated to a temperature suitable for flashing and preferably to a temperature at least about its initial boiling point, ordiiarily to a temperature between about 300 F. and 1100D F., preferably between r750 F. and 950 F. The heated oil is introduced into the upper portion of reaction chamber 32 through inlet conduit l! and header members G5. The oil slowly flows from perforations in header members and flows downwardly over the headers and drips onto the baiiies below the headers so as to cause the dispersion of the oil over the surfaces of the various baffles as a thin oil film thereon. vapors are flashed from the oil material with substantially no formation of tar mist. Any minute amount of tar mist which may be formed solely by flashing vapor from the thin oil film is knocked down upon contact with other baffles in the upper portion of chamber 32. Unvaporized materials iiow downwardly over the surfaces of the various baies as thin films and gravitate from the saw tooth-like projections onto the surfaces and into the pores of pebbles making up the pebble mass within chamber 32. The liquid is heated by the direct heat exchange with the hot pebbles in chamber 32 and an additional portion of the oil is vaporized thereby.

Superheated steam, preferably at a temperature within the range of between 800 F. and 850 is introduced into the interior cf the baffle member 39 through inlet conduit :i2 and header member M. The steam is ejected downwardly along the inner surface of baffle member 3Q and escapes through perforations in baffle member 3S flowing upwardly through the thin layer of pebbles covering baffle member 39 facilitating vaporization of the oil. The steam is introduced into the confines of baffle member 39 at a rate of between about 1/4 pound to l pound of steam per pound of oil feed. This flow of steam aids in the separation of vaporous materials from the pebbles and the steam and the vaporous materials are caused to ilow upwardly from chamber 32 into vapor phase reaction chamber 2 l. The gaseous materials are collected within that chamber below the support member 3S where good mixing thereof is obtained. The gases then flow upwardly through perforations 31 in support member 36 and through the hot pebble mass within Cil chamber 2l. The gaseous materials are converted within vapor phase reaction chamber 2i to form oleiinic materials which are recoverable in purity of about 95 per cent. Hydrogen is also formed as a product in reaction chamber 2i. Reaction products obtained from vapor phase reaction 2| are removed therefrom through gaseous effluent conduit 21 to recovery system 28. Condensation of normally liquid oleiinic materials is obtained within the recovery system and olenic liquid is removed therefrom through liquid eiiiuent conduit 3| and olefinic gaseous materials are removed therefrom through gaseous efliuent conduit 29. The liquid oleiins boil in a range above F. depending specically upon the severity of treatment. The liquid recovered from the separation or recovery system is at least per cent oleiins.

Unvaporized liquid materials on the surface of pebbles within reaction chamber 32 are subjected to additional heat treatment during which a part of the liquid material is vapcrized. Material which is vaporized at a level below baiie member 38 passes upwardly into the void spec below baffle 39 and is collected through header member 45 and is removed from the reaction chamber through conduit 48 to recovery system 41. Normally liquid materials are condensed in recovery system l? and coker liquid removed from the recovery system through liqu eiiuent conduit 39 while normally gaseous Coker m is removed therefrom through conduit The unvaporized hydrocarbon material is converted to coke in and on the pebbles and is carried downwardly through reaction chamber f2 with those pebbles. This unvaporized material constitutes tar which is maintained on the surface of the pebbles within reaction chamber 32 for a period of between 30 and 60 minutes. This contact time is sufficient to coke the tar and release any desirable gaseous product therefrom. The coke covered pebbles are removed from the bottorn of chamber 32 through pebble outlet con i1"- and a small portion of the coke cov pebbles is introduced into heater chamber' through pebble Conduit 53. Steam is oy to superheat the steam passing throu. i cc 55, preferably to a temperature within the range of between 800 F. and 850 F. pebremoved from the bottom of heater c 55 and are combined with the pebb" through pebble conduit 54 and are elc a" the upper portion of pebble heater chamber .i. The steam which is introduced into the lower portion of reaction chamber 32 through header member 5! is in an amount of about 0.1 pound or less per pound of oil. This steam is utilized only to assure positive flow of gas upwardly through the reaction chamber.

Better understanding of this invention will bc obtained upon reference to the specifi-c exampie below.

Speczjc example An oil feed is heated to about 850 and is introduced onto the surface of a plurality of members as thin oil films so as to prevent splashing in an oil flashing zone. The oil flashed therein and unvaporized oil is gravitate-J. onto the surface of a gravitating mass of pebbles which is l9 at about 950 F. Specific properties of the oil feed, flashed vapors, and liquid oil gravitated onto the pebble mass are set forth below as Table I.

Steam is introduced into the oil coated pebble mass a short distance below its top layer. The steam which is superheated to about 800 aids greatly in gently Vaporizing the lighter constituents.

The vapors are passed into the lower portion of a vapor phase cracking zone and countercurrent to a gravitating mass of hot pebbles therein. Pebbles are introduced int-o the upper portion of the vapor phase cracking zone at about 1250 F. The vapors are cracked into predominantly olefin material. Products resulting from the reaction in the vapor phase cracking zone are passed to a recovery zone from which a gaseous fraction and a liquid fraction are obtained. The gas fraction represents about 45 weight per cent of the vaporous products fed to the recovery zone. An analysis of the gas fraction is set forth below in Table II.

Table II Mol Percent labout 95% pure. 1

Butylenc The oil which is not stripped from the pebbles by flow of steam through the top layer of the pebble mass is slowly converted to coke in a reaction zone. Vapor which is released in the reaction Zone during the colring step is removed therefrom as coker gas. Coker gas is mainly parafnic. The coker gas is passed to a recovery zone from which a gaseous fraction and a liquid fraction are obtained. An analysis of the gas fraction is set forth below in Table III. The gas fraction represents about weight per cent of the vaporous products fed to the recovery zone.

Table III Gas: Mol per cent H2 4.2 C114 29.7 C2H2 1.2 C21-1ro 23.3 CsHc 4.1 CaHs 19.5 Celis 4.6 C4IIio 134 Gasoline and gas oil form the major portion of the ecker products. Of the liquid fraction, gasoline comprises about weight per cent and gas oil about 80 weight per cent.

The amount of coke which is formed depends 10 mainly on the type of oil which is fed. Coke on the surface of pebbles may be used to supply heat for a feed preheater, a steam superheater, and the pebble heater, depending upon the amount of coke produced.

I have disclosed that the oil feed is heated to a temperature which is suitable for flashing. That temperature is not necessarily as high as the initial boiling point of the feed (STP). Flashing conditions are obtained in one respect by reducing the partial pressure of the feed oil by the introduction of steam into the flash chamber through inlet header 41 and the top of the pebble bed.

Many modifications of this invention will be apparent to those skilled in the art upon study of this disclosure. Such modifications are believed to be within the scope of the invention disclosed herein.

I claim:

l. The process of converting hydrocarbon oil which comprises the steps of heating said oil to a temperature suitable for flashing and within the range of between 300 F. and 1l00 F. in a first heating zone; slowly admitting said heated oil into a flash zone at a plurality of dispersed points; gravitating said oil onto and over downwardly projecting bales as thin films in said ash zone; iiashing vapors from said gravitating oil; gravita-ting pebbles into a Vapor phase reaction Zone at a temperature within the range of between 1100o F. and 1600 F. and downwardly therethrough as a contiguous pebble mass; gravitating said pebbles through said ash Zone and into a liquid phase reaction zone at a tempera ture within the range of between 900 F. and 1400 F. and downwardly therethrough as a contiguous pebble mass; depositing oil which drips from said baiiies in said iiash zone on the surface of pebbles within said liquid phase reaction zone; introducing superheated steam beneath the surface of said pebble mass in said liquid phase reaction zone at a rate of between 0.25 and 1 pound of steam per pound of oil feed; passing said steam and any vapors stripped thereby from said oil upwardly through said flash zone and with said flashed vapors from said dash Zone into the lower portion of said vapor phase reaction Zone; passing said vapors in direct heat exchange with and countercurrent to the ilow of said pebbles in said vapor phase reaction Zone so as to cause the conversion of said vapors predominantly to oleiins; removing a predominantly olen product stream from the upper portion of said vapor phase reaction Zone; reacting liquid oil on the surface of said pebbles in said liquid phase reaction zone so as to convert vaporizable materials to predominantly paraiijnic products and to convert non-vaporizable inaterials to coke on said pebbles; removing said predominantly parafnic products from within the upper portion of said pebble mass in said liquid phase reaction Zone in a gaseous form; gravitating said coke covered pebbles from said liquid phase reaction zone; oxidizing and regenerating said coke from said pebbles so as to heat same; and reintroducing said pebbles into said vapor phase reaction Zone at a temperature in the range of between 1100 E. and i600" F.

2. The process of claim 1 wherein steam at a temperature within the range of between 800 F. and 850 F. is introduced into the lower portion of said liquid phase reaction zone at a rate of up to 0.1 pound per pound of oil feed.

3. The process of claim 1 wherein said hydrocarbon oil has an API gravity above 10.

Ll. The process of converting hydrocarbon oil which comprises the steps of heating an oil having an API gravity within the range of between 10 and 25 to a temperature of at least about its initial boiling point and Within the range of between 750 F. and 950 F. in a rst heating zone; slowly admitting said heated oil into a ash zone at a plurality of dispersed points; gravitating said oil onto and over downwardly projecting baffles substantially without splashing and as thin lms in said flash zone; flashing vapors from said gravitating oil; gravitating pebbles into a vapor phase reaction Zone at a temperature within the range of between l150 F. and 1350" F. and downwardly therethrough as a contiguous pebble mass; gravitating said pebbles through the central portion of said ash zone and into a liquid phase reaction zone at a temperature within the range of between 950 F. and l100 F. and downwardly therethrough as a contiguous pebble mass; depositing oil which drips from said baffles in said flash zone on the surface of pebbles within said liquid phase reaction zone; introducing steam at a temperature within the range of between 800 and 850 F. beneath a thin layer or" said pebbles within said liquid phase reaction zone at a rate of between 0.25 and 1 pound of steam per pound of oil feed; passing said steam and any vapors stripped thereby from said oil upwardly through said flash zone and with said flashed vapors from said flash Zone into the lower portion of said vapor phase reaction zone; passing said vapors in direct heat exchange with and countercurrent to the flow of said pebbles in said vapor phase reaction zone so to cause the conversion of said vapors predominantly to olens; removing predominantly oleiinic product stream from the upper portion of said vapor phase reaction zone; reacting liquid oil on the surface of said pebbles in said liquid phase reaction Zone so as to convert vaporizable material to predominantly paraiinic products and to convert non-vaporizable materials to coke on said pebbles; removing said predominantly parai-nic products irom within the upper portion of said pebble mass in said liquid phase reaction zone in a gaseous form; gravitating said coke covered pebbles from said liquid phase reaction zone; oxidizing and regenerating said coke from said pebbles so as to heat same; and reintroducing said pebbles into said vapor phase reaction zone at a temperature in the range of between 1150 F. and 1350 F.

5. The process o claim 4 wherein steam at a temperature within the range of between 800 F. and 850 F. is introduced into the lower portion or said liquid phase reaction Zone at a rate up to 0.1 pound per pound of oil feed.

6. The process of claim 4 wherein said pebbles are very porous in structure and said oil which is deposited on said pebbles in said liquid phase reaction Zone is deposited on the surface and in the pores of said pebbles.`

7. The process of claim 4 wherein a portion of said coke-bearing pebbles is passed to a first heater Zone; a controlled amount of oxygen is introduced into the lower portion of said first heater zone so as to oxidize a portion of said coke. in said heater zone; steam is passed in indirect heat exchange with oxidation products 0btained by the oxidation of said coke in said irst heater zone at such a rate as to heat said steam to a temperature within the range of between 800 F. and 850 F.; introducing said steam into the bottom portion of said liquid phase reaction zone in an amount only sufcient to maintain positive gaseous upow in said liquid phase reaction zone; removing said pebbles from the lower portion of said first heater zone and combining them with the balance of said coke-bearing pebbles from said liquid phase reaction Zone and passing said pebbles to a second heating zone for oxidizing and regeneration.

8. The process of claim '7 wherein oxygen is introduced into the lower portion of said second heating zone; introducing a controlled amount of water into the lower portion of said second heating Zone so as to control the pebble outlet temperature within a range of between 1300" F. and 1800 F.; gravitating said heated pebbles from said second heating zone into said vapor phase reaction Zone; and removing gaseous eiiluent from the upper portion of said second heating Zone.

9. Improved pebble heater apparatus which comprises in combination an upright elongated closed pebble heater chamber; pebble inlet means in the upper portion of said pebble heater chamber; gaseous eiuent outlet means in the upper portion of said heating chamber; air inlet means in the lower portion of said heating chamber; water fog inlet means in the lower portion of said heating chamber; an upright elongated closed vapor phase reaction chamber below said heater chamber; a pebble conduit extending downwardly from the bottom of said heater chamber into the interior of said vapor phase reaction chamber; sealing gas inlet means connected to said pebble conduit between said heating chamber and said vapor phase reaction chamber; a rst recovery means; gaseous euent conduit means extending from said iirst recovery means; liquid efiiuent conduit means extending from said rst recovery means; gas- H eous eilluent outlet conduit means extending between the upper portion of said vapor phase reaction chamber and said recovery means; a perforate refractory load-supporting dome within the lower portion of said vapor phase reaction chamber dividing said vapor phase reaction chamber into a reaction zone above said dome and a distribution zone below said dome; an upright elongated closed liquid phase reaction chamber below said vapor phase reaction chamber; gaseous eiiiuent conduits extending from the top of said liquid phase reaction zone to said vapor phase reaction zone below said perforate refractory dome; a pebble conduit extending coaxially downwardly from said refractory dome in said vapor phase reaction chamber into the interior of said liquid phase reaction chamber; a plurality of circular inlet headers of different diameters having outlet openings spaced apart in their upper surfaces provided in the upper portion of said liquid phase reaction chamber and encircling said pebble conduit therein; a irst plurality of circular baffles of different diameters in the upper portion of said liquid phase reaction chamber disposed so that one said baille member extends downwardly from within the circle formed by and adjacent each said circular header member and outwardly to a circle at least as large as the outer diameter of the circle formed by the header member immediately above; an oil heater; oil

conduit means extending between said oil heater and said circular header members within said liquid phase reaction chamber; a perforate conical baille having an outer diameter somewhat smaller than the inner diameter of said liquid phase reaction chamber disposed coaxially with and a short distance below the outlet end of said pebble conduit in the upper portion of said liquid phase reaction chamber; steam inlet means within the upper portion of said perforate conical baille and having outlet openings eX- tending parallel to the surface of said conical baille; steam conduit means extending through the wall of said liquid phase reaction chamber to said steam inlet means within said perforate conical baille; outlet header means within the lower portion of said perforate conical baffle; second recovery means; gaseous eluent conduit means extending from said second recovery means; liquid effluent conduit means extending from said second recovery means; gaseous efiluent conduit means extending from said outlet header in said liquid phase reaction chamber to said recovery means; a disc baille Within said perforate conical baille in said liquid phase reaction chamber .intermediate said steam inlet means and said outlet header means and being spaced from the wall of said perforate conical baille; pebble outlet means in the bottom of said liquid phase reaction chamber; elevator means connected at its lower end portion to said pebble outlet means from said liquid phase reaction chamber and at its upper end portion to said pebble inlet means in said heater chamber; and steam inlet means connected to the lower portion of said liquid phase reaction chamber.

10. Pebble heater apparatus of claim 9 wherein a plurality of circular bailles of diilerent diameters encircle said pebble conduit in the upper portion of said liquid phase reaction chamber and are disposed above said circular headers.

11. The process of claim 1 wherein said pebbles are highly porous.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,806,997 Joseph May 26, 1931 1,957,649 Houdry May 8, 1934 2,387,378 Wolk Oct. 23, 1945 2,448,922 Simpson et al Sept. 7, 1948 2,489,628 Evans Nov. 29, 1949 2,546,625 Bergstrom Mar. 27, 1951 2,547,015 Kirkbride Apr. 3, 1951 

1. THE PROCESS OF CONVERTING HYDROCARBON OIL WHICH COMPRISES THE STEPS OF HEATING SAID OIL OF A TEMPERATURE SUITABLE FOR FLASHING AND WITHIN THE RANGE OF BETWEEN 300* F. AND 1100* F. IN A FIRST HEATING ZONE; SLOWLY ADMITTING SAID HEATED OIL INTO A FLASH ZONE AT A PLURALITY OF DISPERSED POINTS; GRAVITATING SAID OIL ONTO AND OVER DOWNWARDLY PROJECTING BAFFLES AS THIN FILMS IN SAID FLASH ZONE; FLASHING VAPORS FROM SAID GRAVITATING OIL; GRAVITATING PEBBLES INTO A VAPOR PHASE REACTION ZONE AT A TEMPERATURE WITHIN THE RANGE OF BETWEEN 1100* F. AND 1600* F. AND DOWNWARDLY THERETHROUGH AS A CONTIGUOUS PEBBLE MASS; GRAVITATING SAID PEBBLES THROUGH SAID FLASH ZONE AND INTO A LIQUID PHASE REACTION ZONE AT A TEMPERATURE WITHIN THE RANGE OF BETWEEN 900* F. AND 1400* F. AND DOWNWARDLY THERETHROUGH AS A CONTIGUOUS PEBBLE MASS; DEPOSITION OIL WHICH DRIPS FROM SAID BAFFLES IN SAID FLASH ZONE ON THE SURFACE OF PEBBLES WITHIN SAID LIQUID PHASE REACTION ZONE; INTRODUCING SUPERHEATED STEAM BENEATH THE SURFACE OF SAID PEBBLE MASS IN SAID LIQUID PHASE REACTION ZONE AT A RATE OF BETWEEN 0.25 AND 1 POUND OF STEAM PER POUND OF OIL FEED; PASSING SAID STEAM AND ANY VAPORS STRIPPED THEREBY FROM SAID OIL UPWARDLY THROUGH SAID FLASH ZONE AND WITH SAID FLASHED VAPORS FROM SAID FLASH ZONE 